The widely-used input device of a computer includes for example a mouse device, a keyboard device, a trackball device, or the like. Among these input devices, the mouse device is the most prevailing because it is very easy-to-use for most users. When a mouse device is held by the palm of a user, the user may move the mouse device to control the movement of a cursor shown on a display screen of the computer.
Hereinafter, the structure and the function of a conventional mouse device will be illustrated with reference to FIG. 1. FIG. 1 schematically illustrates the connection between a conventional mouse device and a computer system. The computer system 15 comprises a computer host 151 and a display screen 152. The computer host 151 is in communication with a mouse device 1 and the display screen 152. The computer host 151 has a connecting port 1511. A graphic-based window 1521 and a cursor 1522 are shown on the display screen 152. The mouse device 1 is used for controlling the cursor 1522 to have the computer host 151 execute a corresponding command. The mouse device 1 comprises a main body 10, a left button 11, a right button 12, a scroll wheel 13, and a connecting cable 14. The left button 11 is disposed on the main body 10 and located at a left side of the scroll wheel 13. In addition, the left button 11 is exposed outside the main body 10. By pressing down the left button 11, a left button signal is generated. The right button 12 is disposed on the main body 10 and located at a right side of the scroll wheel 13. By pressing down the right button 12, a right button signal is generated. The scroll wheel 13 is disposed within the main body 10 and partially exposed outside the main body 10. By rotating the scroll wheel 13, a corresponding scrolling signal is generated. The connecting cable 14 is connected with the main body 10 and protruded outside the main body 10. When the connecting cable 14 is connected with the connecting port 1511, the communication between the mouse device 1 and the computer system 15 is established.
Generally, for different users, the sizes of the palms and the lengths of the fingers are different. Since the mouse body of the general mouse device has a fixed size, the mouse device may only comply with the palms and fingers of specified users. In other words, the size of the mouse body of the general mouse device fails to comply with the palms and fingers of some other users. If the unsuitable mouse device is used for a long time period, the procedure of operating the mouse device usually incurs unacceptable fatigue of the user's hand. For solving the above drawback, a mouse device with an adjustable shape is introduced into the market. For example, China Patent Publication No. CN203746021 discloses a mouse device with increasable volume. The volume of the mouse device is adjustable according to the size of the palm. However, the mouse device with increasable volume has a very simple structure and is not aesthetically pleasing. Moreover, the shape-changing element of the mouse device is rough. While the shape of the mouse is changed, it is necessary to use a fastening knob to fix the shape-changing element. Consequently, the mouse device with increasable volume is not user-friendly.
Therefore, there is a need of providing a mouse device with an adjustable shape, aesthetically-pleasing appearance and user-friendliness.